Birds

Nesting birds on sound islands take a hit from Hurricane Arthur

By Maria Logan

AM Oystercatcher nest Maria Logan

American oystercatcher nest by Maria Logan

Young Brown Pelicans Beacon Island Vankevich 2014-07-06 16.21

Young Brown Pelicans on Beacon Island after Hurricane Arthur. Photo taken with long lens from a boat by Peter Vankevich

It’s summertime and Ocracoke is in full swing. There is a frenetic energy about the island as visitors flock to paradise and residents work hard to welcome them. This energy is mirrored on many of the smaller islands throughout the Pamlico Sound. Nesting season, from March through October, is a busy time for waterbirds.

These islands, some no more than shell mounds, are chock-full of several species of nesting birds. Black skimmers, three species of terns, American oystercatchers, brown pelicans, three species of gulls, a variety of herons and egrets, and others all nest here. Some prefer building elevated nests in vegetation. Others prefer to nest directly on the ground.

Like Ocracoke Village, winter on Beacon, Shell Castle, and North Rock islands, is a quieter time, but as springtime rolls in birds begin vying for prime nesting spots. Oystercatchers, specifically, meet up with their life-long mate and usually return to the same territory that they’ve established year after year. They will defend their turf quite aggressively from other pairs looking for a piece of the territorial pie. With territory established, parent birds begin the challenging task of raising their young.

Larger predatory birds, like black-crowned night herons and great black-backed gulls, are also nesting, requiring extra vigilance from non-predatory nesters. Yet even when surrounded by avian predators, they can defend and successfully raise chicks. The oystercatchers will fly fast and hard at a predatory bird that is attempting to steal an egg or chick. Common terns, though not large, also aggressively defend their nests and can pack quite a punch when they dive and strike with their beaks.

Weather and loss of habitat due to erosion are other variables that can determine the fate of nests. The early arrival of Hurricane Arthur took its toll on many of the ground nesters this year. Ground nests on these low-lying islands are simply no match for high winds and waves. Oystercatchers, terns, and black skimmers took the biggest hit while brown pelicans, whose nesting numbers were up from the 2011 census, lost chicks but fared better than other species.

In addition to these challenges, human encroachment during nesting season can have regrettable impacts for several reasons. The natural camouflage of eggs and chicks protects them from predators, but can make them vulnerable to footsteps. Data collecting is calculated and methodical to keep disturbance to an absolute minimum. Keeping a safe distance from the islands allows the bustling nesting season to continue undisturbed. When an adult is forced to fly away from its nest or chicks, there is a window of opportunity for predators to swoop in and make a meal of the unprotected young.  Exposure to the elements is another hazard for the eggs and chicks when adults are forced to flee from humans or dogs. Some adults are quicker to fly away than others, but regardless of species, their attention is often focused on the approaching human or predator. In these instances, feeding and caring for the young is interrupted, also leaving them vulnerable. Signs on the islands remind people that these areas are closed to humans and dogs during the sensitive nesting season.

Chicks that successfully fledge from these and other nesting habitats contribute to the state bird population. Many of these species will fly far and afield on their annual migrations. For instance, banding data shows common terns have traveled as far as Brazil. Brown pelicans typically winter in the southeast U.S., but some have been recorded in Cuba. As adults, this year’s fledglings will find their own nesting grounds to begin another generation.

Maria Logan has worked for Audubon North Carolina as a biological science technician on Beacon, Shell Castle and North Rock Islands for the past four years.